FEMTO- Meaning of FEMTO- in English femto- BrE AmE ¦fem p t ə ʊ AmE ¦fem p t oʊ▷ — femtogram ˈfem p t ə ʊ ɡræm AmE -oʊ- Longman Pronunciation English Dictionary. Английский словарь произношений Longman. 2012